No, it is not a still, it is in fact the 3.5 MHz pass section for a 3.5/7 MHz SO2R diplexer I am building.
Parts are gross and the reason for this is that I am aiming for very low loss.
I ran out of copper tubing so it is missing a couple off shunt inductors, but when those are in place it is ready for tuning and trimming.








Here is an offer from my friend Dom F1FRV. In need for something like this, make your move fast as he build 1st class electronics!!

Jeu de circuits imprimes pour ampli avec triode
Jeu complet de 4 circuits iùprimes pour ampli de puissance avec triode.
Double face, trous metallises, 2 vernis epargne et 1 serigraphie.
Carte logique, carte cathode, carte temporisation arret ventilateur, carte pour face avant boitier avec leds et inters.
Toutes les documentations: schemas, nomenclatures, docs des composants etc. sont disponibles.
Voir http://f1frv.free.fr/Flea_Market.html.
QSJ 50 Euros (hors frais de port et Paypal).
73s de Dom
Full set of printed circuit boards for triode power amplifier
Set of 4 PCBs dual side, plated thru holes, 2 resist varnishes, and 1 silkscreen.
Logic board, cathode & meters card, blower delayed stop card, front plate card with leds & switches.
All documentation, schematic diagrams, bill of materials, datasheets etc. are available.
See http://f1frv.free.fr/Flea_Market.html.
QSJ 50 Euros (ex shiping and Paypal fees).
73s de Dom.

Last night I got a Foscam FI9821W ip-cam to play with, but within an hour it was broken because the firmware upgrade failed. I was simply trying to upgrade from to the version.
The camera interface reported that the update was successful but the camera never came online again. It does its servo calibration routine when powered but that is all.
Searching the internet I can see that there are several reports of this problem but as far I can see no cure other than asking the supplier for a RMA. I am not interested in sending this cheap device half around the world for a repair or exchange unit, so I decided to try to fix it myself.
Luckily, I was able to get it going again and the process was fairly simple.

Warning:  This process worked for my problem but I cannot guarantee that it will work for you.

You need:
-To void your warranty.
-Some serial TTL interface for your computer.
-Your favorite terminal computer application.
-Soldering iron.
-Small screwdriver.
-Download version of firmware.

Remove bottom cover unscrewing four screws. Then solder your TTL interface according to picture below.


Then launch your terminal program with these settings. Of course you will have to find your own com port number.

18-06-2013 18-16-18

If you have done it right you shold get text flying over your screen when powering the camera.
This text will after a little while halt.
With your wired network connected to the camera execute the following commands:

First press enter or esc to get to the promt.
type: “/etc/init.d/S80network” + enter
type: “ifconfig eth0 netmask broadcast” + enter (you will have to adjust the ip address so it fits in your network)

Now the camera web server should be accessible from your browser again. Point it to http://your ip address above:88 (in my case
Camera will not work and lot of info will be missing because many processes are not running, never mind this.
Then go to the system – firmware upgrade page and upload version firmware.
When camera is done with the upload and reboot it should be working again.

After this downgrade, I was successful in upgrading to version I have several times tried to downgrade and thereafter upgrade but I have not been successful in reproducing the error.

Today I decided to try out the pa0rdt Mini Whip design.

I have only have tested it for å few hours, but so far I find it performing a lot better on the LF and MF spectrum compared to my other Active Antenna discussed I an earlier post on this site.

On shortwave up to 20m it seems to perform about the same BUT there is a very important difference between the two; pa0rdt design dos not overload when I simultaneously transmit on other bands. My other active antenna makes all kinds of crazy bi-products while transmitting.

I think I was a bit too hasty with my first report regarding the difference in performance of the two active antennas. Now, after a little more use I think they perform almost equally. The pa0rdt whip has a bit more gain but the SNR seems to be about the same.


pa0rdt Mini Whip Amplifier without whip

pa0rdt Mini Whip Amplifier without whip


17-02-2013 pa0rdt-Mini-Whip

pa0rdt Mini Whip Amplifier


Here is an active antenna for higher LF and MF frequency range using an U310 N-Channel JFET as amplifier.
Antenna are based on a la8ak (sk) design. It has a decent performance given its small size.
However, on lower LF and VLF range it performs poorly.

A little tip for anyone interesting using this design or similar designs. Do not power it by a noisy switching power supply. Switching noise will go straight into the receiver.


Bias tee PCB

Bias tee PCB


Left: Remote amp. with telescopic car whip Right: Bias tee

Left: Remote amp. with telescopic car whip Right: Bias tee


Remote amp. and antenna

Remote amp. and antenna



Bias tee mounted in a nice box

Bias tee mounted in a nice box


Blue LED in remote amp. shows that power is present. Green LED on bias tee indicates normal current load.

Blue LED in remote amp. shows that power is present. Green LED on bias tee indicates normal current load.


Remote antenna amplifier schematic

Remote antenna amplifier schematic


Bias tee schematic

Bias tee schematic


Here’s the SV1EIA usb2sdr board controlling the Si570 chip on the vfo kit from K5JHF/K5BCQ, the MCU and display unit are of course removed. And the Si570 board is clocking the LA6NCA QSD unit. I haven’t calibrated anything yet, but it works fine.

Simple usb2sdr receiver setup. Top: K5JHF/K5BCQ Si570 board. Left: LA6NCA QSD board. Right: SV1EIA USB2SDR board.

Receiving wspr with the simple sdr setup.

Yesterday I received the Si570 Controller and Frequency Generator Kit by K5JHF and K5BCQ.
And today, after 3 to 4 hours work the kit was ready for a test spin. My unit has the LVDS Si570 chip, the FIN-1002 LVDS to LVTTL converter with the TC1-1TG2+ output transformer. Here are a few pix…..

The Si570 kit

A few hours work and the kit is ready and working.

Generator output @ 56.320Mhz










There has been some interest in the Picaxe GPS NMEA-0183 Decoder which I use to time the keying of my wpsr beacon.
The Picaxe chip decodes the time data in the $GPGGA sentence from the GPS unit and then print the UTC time on the lcd display. In addition it set a output at the start of every even minute for keying the wspr beacon. That’s all it do with the current 18X chip.
I am planning an upgrade to the 18M2 chip which is a lot more powerful and has got more functions then the current 18X chip.
With the 18M2 I am planning to display some of the other GPS information, like position, signal strength, number of satellites, etc.  It’s not that the 18X chip can’t do this extra information bit. But these task will put a lot more strain on processing and communication so I fear the accuracy of the keying will suffer.

Picaxe GPS NMEA-0183 Decoder

 >> Download full size scheme <<

            ; *****************************************************************
            ; ************************* Picaxe Project ************************
            ; *****************************************************************
            ;     Filename:         GPSDO Display unit v0.4.bas        
            ;     Date:             25.02.2012
            ;     File Version:     0
            ;     Written by:       LA6TPA Geir Aarnes
            ;     Function:         Decode NMEA data from GPS unit
            ;     Last Revision:    4
            ;     Target PICAXE:    18X
            ; *****************************************************************
            ;     Revision history
            ;     Intitial code                 GPSDO Display unit v0.1.bas
            ;     First working version         GPSDO Display unit v0.2.bas
            ;     WSPR trigger added            GPSDO Display unit v0.3.bas
            ;     Code cleanup                  GPSDO Display unit v0.4.bas
            ; *****************************************************************          
            #Picaxe 18X
            SETFREQ m8

            symbol GPS_RxD    =     0                                   ;NMEA data from GPS module
            symbol GPS_1PPS   =     pin7                                ;1PPS signal from GPS
            symbol GPS_TxD    =     B.0                                 ;NMEA data to GPS module
            symbol WSPRtrig   =     B.1                                 ;Triger output for WSPR tx start
            symbol tByte00    =     b0                                  ;Byte for temorary data
            symbol LcdByte1   =     b1                                  ;Byte used by LCD routine
            symbol LcdByte2   =     b2                                  ;Byte used by LCD routine
            symbol tByte03    =     b3                                  ;Byte used by LCD routine
            symbol tByte04    =     b4                                  ;Byte for temorary data      
            gosub init                                                  ;initialise LCD
            pause 10000                                                 ;wait for GPS to boot
            serout GPS_TxD,T4800_8,(13)
            serout GPS_TxD,T4800_8,("$PRWIILOG,???,V,,,",13,10)         ;turn off all GPS output
            serout GPS_TxD,T4800_8,("$PRWIILOG,GGA,A,T,1,0",13,10)      ;activate GGA sentence
            let LcdByte1 = 1                                            ;set b1 to clear display instruction
            gosub wrins                                                 ;send instruction to LCD

main:       serin GPS_RxD,T4800_8,("$GPGGA,"),B8,B9,B10,B11,B12,B13     ;wait for $GPGGA then receive 6 bytes into B8..B13
            IF b13 <> "0" THEN GOTO LBL01                               ;Check lower part of seconds, skip if not == 9
            IF b12 <> "0" THEN GOTO LBL01                               ;Check upper part of seconds, skip if not == 5
            tByte00 = B11 - 48                                          ;Read lower part of minute and convert ASCII to binary
            tByte00 = tByte00 & %00000001                               ;Mask bit 0 which indicates an ODD minute
            IF tByte00 <> 0 THEN GOTO LBL01
            high WSPRtrig
            pause 500
            low WSPRtrig
LBL01:      LcdByte1 = 1
            gosub wrins
            LcdByte1 = "U"
            gosub wrchr
            LcdByte1 = "T"
            gosub wrchr
            LcdByte1 = "C"
            gosub wrchr
            LcdByte1 = " "
            gosub wrchr
            LcdByte1 = b8
            gosub wrchr
            LcdByte1 = b9
            gosub wrchr
            LcdByte1 = ":"
            gosub wrchr
            LcdByte1 = b10
            gosub wrchr
            LcdByte1 = b11
            gosub wrchr
            LcdByte1 = ":"
            gosub wrchr
            LcdByte1 = b12
            gosub wrchr
            LcdByte1 = b13
            gosub wrchr
            goto main        

init:       let pins = 0                  ;Clear all output lines
            let b4 = 0                    ;Reset variable b4
            pause 200                     ;Wait 200 ms for LCD to reset.
            let pins = 48                 ;Set to 8-bit operation.
            pulsout 3,1                   ;Send data by pulsing enable
            pause 10                      ;Wait 10 ms
            pulsout 3,1                   ;Send data again
            pulsout 3,1                   ;Send data again
            let pins = 32                 ;Set to 4-bit operation.
            pulsout 3,1                   ;Send data.
            pulsout 3,1                   ;Send data again.
            let pins = 128                ;Set to two line operation
            pulsout 3,1                   ;Send data.
            let b1 = 12                   ;Screen on, cursor off instruction
            gosub wrins                   ;Write instruction to LCD

wrchr:      let pins = b1 & 240           ;Mask the high nibble of b1 into b2.
            high 2                        ;Make sure RS is high
            pulsout 3,1                   ;Pulse the enable pin to send data.
            let b2 = b1 * 16              ;Put low nibble of b1 into b2.
            let pins = b2 & 240           ;Mask the high nibble of b2
            high 2                        ;Make sure RS is high
            pulsout 3,1                   ;Pulse enable pin to send data.

wrins:      let pins = b1 & 240           ;Mask the high nibble of b1 into b2.
            pulsout 3,1                   ;Pulse the enable pin to send data.
            let b2 = b1 * 16              ;Put low nibble of b1 into b2.
            let pins = b2 & 240           ;Mask the high nibble of b2
            pulsout 3,1                   ;Pulse enable pin to send data.
            high 2                        ;Back to character mode

>> Download source code file <<

Have thrown together some parts on a plank here. The idea is to make a “lean” power supply to test my crowbar circuit.
Output is 630v with the current limiter (spot light bulb @ 120watt). And the capacity of the filter capacitors is about 1100uF.
This should be enough energy for the preliminary circuit tests.

Crowbar test supply


….to be continued if I survive 🙂

Here is a line of homebrew circuit board that I have made for a amplifier project I am working on. (Which by the way takes forever to comlete 🙂  )
These boards are designed by Dominique F1FRV which have laid down a tremendous effort in designing these boards.
Dominique has done some minor changes to the design since these boards were made, so cards made by his latest instructions will look a bit different from these.